In the fabrication of aircraft structures, drill plates are often clamped against a multi-layer structure in preparation of a multi-hole drilling procedure. In essence, the drill plate acts as a template with hole patterns to be replicated in the multi-layer aircraft structure. In the past, different types of clamping devices have been employed but a major problem arises after several holes have been drilled. Specifically, conventional clamping devices allow incremental movement of the drill plate relative to the work piece, thereby detracting from the required accuracy for drilling.
Attempts have been made in the past to use the first couple of holes drilled as pilot holes and to install bolts or threaded pins in those pilot holes and through the drill plate and structure in an attempt to maintain alignment between the drill plate and structure. However, often the holes are cold worked before the insertion of bolts and the bolt threads can cause damage to the holes which could ultimately result in rupture of the structure.
An additional problem presented by prior art clamping techniques resides in the insufficient clearance and attendant difficulties of working in tight spaces. If threaded bolts are used, working in tight places becomes difficult due to the extension of the bolt or the existence of a fastening nut.